Do not start the service isolate when generating the core library snapshot as it does not load any …

runtime/bin/gen_snapshot.cc

Index: runtime/bin/gen_snapshot.cc
diff --git a/runtime/bin/gen_snapshot.cc b/runtime/bin/gen_snapshot.cc
index 45087b4c502233d3ccac6f0c491e74078ce5a663..20cc410dc753d22662647a0d4dcc96451e79382a 100644
--- a/runtime/bin/gen_snapshot.cc
+++ b/runtime/bin/gen_snapshot.cc
@@ -1031,12 +1031,14 @@ int main(int argc, char** argv) {
 
   // Initialize the Dart VM.
   // Note: We don't expect isolates to be created from dart code during
-  // snapshot generation.
+  // core library snapshot generation. However for the case when a full
+  // snasphot is generated from a script (app_script_name != NULL) we will
+  // need the service isolate to resolve URI and load code.
   char* error = Dart_Initialize(
       NULL,
       NULL,
       NULL,
-      CreateServiceIsolate,
+      (app_script_name != NULL) ? CreateServiceIsolate : NULL,
       NULL,
       NULL,
       NULL,